package com.dmagic.cms.common.util;

import java.security.MessageDigest;

/**
 * Password encryption and authentication class
 * 
 * @author songlin.li
 */
public class CipherUtil {

     
    /**
     * @description : Digital-to- hexadecimal character of the mapping array
     */
    private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d",
            "e", "f" };

    /**
     * @description :generate MD5 Password
     * 
     * @author songlin.li
     */
    public static String generatePassword(String inputPassword) {
        return encodeByMD5(inputPassword);
    }

    /**
     * @description : Verify the password entered is correct
     * @param password Encrypted password
     * @param inputPassword Enter password
     * @return Verify the results，TRUE or FALSE
     * @author songlin.li
     */
    public static boolean validatePassword(String password, String inputPassword) {
        if (password.equals(encodeByMD5(inputPassword))) {
            return true;
        } else {
            return false;
        }
    }

    /**
     * @description : MD5 encryption on a string
     * @author Solex
     */
    private static String encodeByMD5(String originString) {
        if (originString != null) {
            try {

                MessageDigest md = MessageDigest.getInstance("MD5");
                byte[] results = md.digest(originString.getBytes());
                String resultString = byteArrayToHexString(results);
                return resultString.toUpperCase();
            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }
        return null;
    }

    /**
     * @description :Convert byte array to hexadecimal string
     * @param b
     * @return
     */
    private static String byteArrayToHexString(byte[] b) {
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++) {
            resultSb.append(byteToHexString(b[i]));
        }
        return resultSb.toString();
    }

    /**
     * @description : A byte into a hexadecimal string of the form
     * @param b
     * @return
     */
    private static String byteToHexString(byte b) {
        int n = b;
        if (n < 0)
            n = 256 + n;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }
    
    public static void main(String[] args){
        System.out.println(generatePassword("1234"));
    }
}
